Back to school this week. Open the doors to the children. And then lock them again.

A new Ontario ministry of education policy mandates that all doors at all elementary schools should be locked, with the front door having a security system to buzz in all visitors.

Like most rural communities, our local school is not just a school, but a vital centre for the community. While the first- to eighth-graders are in their classes, their younger brothers and sisters are often down the hall in the “early years centre” where parents bring their babies and toddlers to play.

It didn’t take long. A four-year-old Scarborough boy wandered into the wrong classroom on his first day in school, wearing the wrong nametag, and wasn’t immediately spotted. Cue panic: The police were notified, an alert went out, dozens of police with a K-9 unit turned up to scour the neighbourhood, terror spread. The little boy watched it all obliviously, until teachers spotted the mistake.

Later the same day, another four-year-old, named Alexander, got off the bus at the wrong stop after classes. He wasn’t far from home and was quickly spotted by a daycare worker who noticed a tag on his backpack and called the school. The principal promptly arrived to pick him up and return him to his parents. The bus company delivers almost 50,000 kids a day on 1,600 routes, but Alexander’s plight made local newspapers, radio bulletins and Twitter updates. His father was irate, the bus company was on the hot seat, experts were consulted to discuss what could be done to prevent a recurrence. The notion that, in a city of several million, a child occasionally will get off at the wrong stop, wasn’t considered.

Security is a legitimate concern — especially where children are concerned. And parents naturally slip into terror mode whenever a possible threat to their child arises. But Canadian schools now take the cake when it comes to hitting DEFCON 1 whenever a kid gets off at the wrong stop or spots a peanut in the lunch room.

This hysterical spirit now has found its way into province-wide legislation. As Raymond J. de Souza wrote in Thursday’s edition of the National Post, an Ontario law — hastily drafted to respond to last year’s Sandy Hook elementary-school shootings in Connecticut — requires that the province’s schools impose lock-and-buzzer policies on all building entrances during school hours — even small schools in safe areas where everyone knows everyone. Thanks to former Premier Dalton McGuinty’s Liberal government, every mother delivering a forgotten lunch now has to be approved before she can get in the door.

The driver of Alexander’s bus had a list identifying how many kids were to get off at each stop, but wasn’t allowed to know their names for “security” reasons. The bus company had considered providing photographs to the drivers, but again feared unspecified “security” concerns. Over-reacting in the approved manner, the company is now considering radio frequency identification tags that could be attached to backpacks so every child on every bus could be monitored at every moment. A decade ago, this would have seemed idiotic, or evidence of a creeping police state. Now it’s seen as sensible corporate practice.

Last year, a suburban Toronto woman asked city council to cut down trees near her daughter’s school, because they dropped acorns, to which her child was allergic. Thankfully, she came in for considerable criticism for trying to “child-proof” the world rather than simply teaching her child to avoid acorns. (“For as many people that may be allergic to acorns, I’m sure there’s a lot of people that are allergic to bees,” said one councilor sensibly. “What are we going to do about that? Are we going to exterminate all the bees?”) But in coming years, as the mania for safety becomes more acute, who knows? Acorns may become the new peanuts.

We must resist the impulse to respond to every isolated tragedy with new regulations

Tragedies do happen. A 14-year-old Toronto girl was killed this week when she was hit by a truck near a school. It was a tragic event, certainly. But the response from the local councillor was farcical: a call to consider banning trucks near schools any time students are likely to be outside. Why not parks and hospitals, while we’re at it?

Canadian schools are extremely safe. As Father de Souza noted Thursday, there hasn’t been a shooting at a Canadian elementary school in two decades. And tragedies such as the 2009 abduction of Victoria Stafford near her school are rare: Indeed, to the limited extent children abductions occur in Canada, children are far more likely to be taken from their home by an estranged family member.

We, and our politicians, must resist the impulse to respond to every isolated tragedy, or spasm of anxiety, with new regulations and security protocols whose only effect will be to make life more complicated and tiresome for parents and educators.